Heat exchanger



Nov. 22, 1949A w. H. GoELTz l 'l 2,488,523

f HEAT EXCHANGER Filed July s1, 1944 5 sheeIs-sheet'l I I I I I I I I I I I I I I I I I I l lm- 4 l l lum l i; I I I I I I I I I I l I I I I I I I I I l I as mm 4mi 3 sheet's-sheet 2 da HJ@ W. H. GOELTZ Nov. 22, 1949 HEAT EXCHANGER Filed July s1, 1944 Nov.. 22, 1949 W, H, GOELTZ 2,488,623

' HEAT EXCHANGER 'I Filed July s1, 1944 ssheets-sneet s Patented Nov. 22, 1949 HEAT EXCHANGER I Walter H. Goeltz, Kenosha, Wis., asslgnor to Modine Manufacturing Company, Racine, Wis., a corporation of Wisconsin Application July 31, 1944, serial No. 547,424

e claims. (ci. 13s-3s) the temperature of the steam is controlled by a modulating valve which throttles the steam pressure in accordance with the demands of a thermostat set in the heated air stream. Conditions can easily arise such that the final air temperatures are gained by very low, sub-atmospheric steam pressure. Under these conditions the steam condenses in short sections of the tubes at the supply end of the core, leaving the remaining lengths of the tubes relatively cold, and thus only a portion of the air passing through the core will be heated.

Present day practice to combat the above conditions consists in installing, within the main tubes of the core, smaller tubes with perforations along their lengths to meter out the steam into the spaces between the inner and outer tubes. This practice while greatly improving the performance of the cores, results in a series of hot spots where the inner tubes are perforated.

One of the objects of this invention is to increase the eiiiciency of heat exchangers of the type under consideration.

Another object is the provision of means to meter the steam in a uniform, constant manner throughout the entire length of the core, whereby the latter is uniformly heated throughout. its

extent.

Another object is the provision of means to offer less resistance to the steam as it loses its pressure due to friction.

Another object is the provision of means to maintain a substantially constant steam velocity throughout the length of the core.

Another object is the provision of a tapered distributing trough within the main tube whereby to accommodate the increasing volume of condensate along the tube.

Another object is the provision of a tapered distributing trough having a full sized diameter at the steam inlet, thereby avoiding any throttling of the steam at the inlet.

With these and other objects and advantages in View, this invention consists in the several novel features hereinafter fully set forth and claimed.

The invention is clearly illustrated in the drawings accompanying this specication in which:

Fig. 1 is a front elevation, partly broken vout, illustrating a heat exchanger embodying one form of the present invention;

Fig. 2 is a vertical cross section taken substantially along the line 2-2 of Fig. 1;

Fig. 3 is an enlarged central longitudinal section, partly broken away and taken through one of the tubes and its distributing trough;

Fig. 4 is an end elevation of the parts seen in Fig. 3 looking in the direction of the arrow t;

Fig. 5 is a side elevation, partly broken away and partly broken out of a heat exchanger ernbodying a slightly different form of the invention;

Fig. 6 is a vertical cross section taken on the line 6-6 of Fig. 5; and

Fig. 7 is a longitudinal section taken through a tube, its distributing trough and supply and return headers.

Referring to said drawings, and rst to Figs. l. to 4 inclusive, the reference character 8 designates the main frame of the heat exchanger. desirably composed of sheet metal channel members 9 suitably secured together and providing a rectangular frame-like member. Secured to the upper and lower channel members 9 are casings i0, Il, in one of which is contained a supply header i2 and in the other of which is contained a return header I3, provided respectively with inlet and outlet connections it, i5. The ends of the supply header and return header are closed by heads L23, 2t.

Extending betweensaid headers are a plurality of tubes I6 to which are secured fins il inthe usual manner. Secured within the tubes I6 at their inlet ends are distributing troughs I8, desirably of tapered formation, tapering from the inlet ends of the tubes toward their discharge ends.

The edges I9 of each trough (see Fig. 3) taper toward eachother from the smaller end of the trough to its larger end forming a tapered slot or opening 20. The tapered slot or opening 20 yprovides a steam metering slot through which the steam is metered throughout the length of the trough from the interior thereof to the space between the trough and tube.

With the use of a tapered distributing trough tapering from its inlet end to its outlet end, it maintains a constant steam velocity through its length and forces the steam through the metering slot, and by widening the slot between the edges of the trough, from its inlet end to its outlet end, it oers less resistance to the steam as it loses pressure due t friction. Furthermore, the tapering trough makes the steam space between it and the tube greater towards its outlet end tofaccommodate the increasing volume of the condensate along the tube. The trough being full size at its greatest diameter and fitting against the internal wall of the tube it does not throttle the steam.

The headers are formed with ilanged holes to receive the ends of the tubes, and a baille 2| is secured in the supply header above the end of the tubes. The walls of the baille slope downwardly from its medium line to the side walls of the header to provide greater stream inlet area and divide the header into two chambers, one ot which may be considered as an inlet chamber. The baille is provided with holes 22 for the passage of the steam from the inlet chamber of the header to the tubes.

Two rows of tubes are illustrated, those in one row being staggered with respect to those in the other row, and the holes in the baille are also staggered, and staggered with respect to the tubes. In constructingr the heat exchanger brazing or bonding material is applied to the several parts and after assembly the device is placed in a suitable oven and heat is applied thereto, whereby to fuse the bonding material and thereby integrally unite all of the parts of the device.

In operation when steam is admitted to the supply header it flows through the holes 22 in the baille and into the distributing troughs I8. The steam then ilows through the troughs and is metered through the tapered slots thereof into the spaces between the troughs and the tubes in a uniform and constant manner throughout the length of the troughs, thereby heating the entire length of the tubes, from which the heat is radiated by the ilns to the air passing through the core. The condensate collects in the return header and discharges through the return pipe. (Not shown.)

While the above description concerns heat exchangers in which the tubes extend vertically, the tubes may lie at any angle which permits the free discharge of condensate.

In the modied form of the invention illusstrated in Figs. and 6 the general construction is substantially the same as that shown in Figs. 1 to 4 inclusive, except that the supply header |2a and return header i3d are disposed at the lower end of the heat exchanger, with the supply header contained within the return header. In this form of the invention the headers are shown as of cylindrical form, although this is not essential to the invention. The ends of the supply header I2a and return header |3a are closed by heads 23a, 24a. The supply header has a pipe connection I5a extending down through the lower wall of the return header, and the upper wall I2c of the header is provided with flanged holes for receiving the lower ends of the tapered distributing troughs I8a. The upper wall l3c of the return header 13a is also formed with iianged holes aligned with the iianged holes in the supply header for receiving the lower ends of the tubes IBa. As in the other forms of the invenslots 20a which are widest at the small ends of the troughs. The upper. ends of the tubes are closed over the small ends of the troughs, as at 25, and center said ends of the tubes. A cap or other enclosure 2l secured to the upper channel member 9a, as by ilanges 26a, may be used to enclose the upper ends of the tubes.

As in the other form of the invention, a baille Ila is provided in the supply header and is secured to the walls thereof. In this case the banle inclines upwardly from its medium line to the side walls of the supply header and is formed with staggered holes 22a which are also staggered with respect to the troughs.

In this form of the invention the steam enters the distributing troughs at their lower ends and is metered out through the slots into the spaces between the troughs and tubes. To permit the condensate to escape from the tubes, the latter are made of a slightly greater diameter than the greatest diameter of the troughs, thereby leaving annular discharge openings at the lower ends of the tubes. The condensate discharges from these annular spaces into the return header and is carried away by the return pipe (not shown) which is secured in the outlet connection Ha.

While the above description .concerns heat exchangers in which the tubes extend vertically, the tubes may lie at any angle which permits the free discharge of condensate, as shown in Fig. y'1, where each tube |6b surrounds the tapered slotted distributing trough I 8b substantially in the same manner as is illustrated in Figs. 5 and 6.

In this form of the invention one end of the tube is closed and the steam is metered out from .the troughs into the spaces between the troughs and tubes, as in the other forms, and the condensate discharges from the space between the troughs and tubes into the return header. In this form of the invention the tubes are disposed in one row only but double rows of tubes may be used in the same manner as in the other forms above described.

While I have shown and described the distributing troughs as applied to a steam heated heat exchanger, they are adaptable to the distribution of a vaporizing iiuid for refrigeration.

vHaving thus described my invention, it is obvious that various immaterial modications may be made in the same without departing from the spirit of my invention; hence I do not wish to be understood as limiting myself to the exact form, construction, arrangement and combination of parts herein shown and described, or uses mentioned.

What I claim as new and desire to secure by Letters Patent is:

1. In a heat exchanger, a iluid conducting tube having an inlet end, a tapered slotted distributing trough contained in the tube with its larger end disposed at the inlet end of the tube and the slot increasing in width from the inlet end of the tube to the other end thereof.

2. In a heat exchanger, a iluid conducting tube, a tapered distributing trough supported within the tube with its greatest diameter disposed at the inlet end of the tube, said trough being formed with a lengthwise extending slot in its wall which progressively increases in width from the inlet end of the tube to the other end thereof.

3. In a heat exchanger, a fluid conducting tube havingan inlet end, a tapered distributing trough supported within the tube with its greatest diameter disposed at the inlet end of the tube, the

yend disposed at the inlet end of the tube and the slot increasing in width from the inlet endy of the tube to the other end thereof, said other end of'said tube being closed. y

5. In a heat exchanger, a uid conducting tube, a tapered distributing trough supported within the tube with its greatest diameter disposed at the inlet end of the tube, said trough beingy formed .with a lengthwise extending slot in its wall which progressively increases in width from the inlet end ofthe tube to the other end thereof. said other end of said tube being closed.

6. In a heat exchanger, a uid conducting tube having an inlet end and a vclosed end, a tapered distributing trough supported within the tube with its greatest diameter disposed at the inlet end of the tube and converging towardsI said closed end, the .interior of the'tr'ough opening to the space between the trough and tube through a tapered slot in the wall of the trough, and said slot tapering toward the inlet end of the tube. WALTER H. GOELTZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Nam-e Date i 1,117,050 Honigmann Nov. 10, 1914 1,447,688 Reed Mar. 6, 1923 l1,689,927 Newhouse Oct. 30, 1928 1,802,930 Seelert Apr. 28, 1931 1,847,608 Harnett Mar. 1, 1932 2,238,952 Stacey Jr Apr. 22, 1941 FOREIGN PATENTS Number Country Date 255,445 Germany 1--.. Apr. 2, 1912 

